A haemolysed sample.

 If following centrifugation the plasma or serum looks reddish rather than straw yellow, it is likely the sample has haemolysed (FIG. 1.1). In a haemolysed sample some of the red blood cells have lysed (broken open) and their contents have now contaminated the plasma or serum sample. This will cause error in reporting amongst others elevated potassium, magnesium and phosphate. Some analytical methods may be able to negate the effect of the haemolysed sample. Common causes of a haemolysed sample are collection needle gauge too narrow, over vigorous shaking of the sample, underlying haematological disorder, red cells isolated for storage and then stored in water or a non isotonic solution and over physical dispensing of blood from hypodermic syringe to collection tubes.

Figure 1.1: A haemolysed sample